Solid-State Batteries and Dry Electrode Sheets，Technological Symbiosis and Industrial Innovation in the Solvent-Free Era

Amid the evolution of new energy storage technologies toward higher safety, greater density, and lower pollution, solid-state batteries have emerged as a core direction for next-generation electrochemical energy storage, thanks to the fundamental safety breakthroughs brought by solid electrolytes. Meanwhile, dry electrode sheet technology, characterized by its solvent-free nature, cost-effectiveness, and high adaptability, is providing crucial support for the large-scale commercialization of solid-state batteries from the manufacturing end. The in-depth integration of these two technologies is no coincidence; it is an inevitable outcome driven by both technological logic and industrial demands, jointly propelling the lithium-ion battery industry into a new "solid-state + solvent-free" era.

Technological Adaptation: Dry Process Overcoming Manufacturing Bottlenecks of Solid-State Batteries

The wet electrode sheet process, relied upon by traditional liquid lithium-ion batteries, faces inherent incompatibilities in solid-state battery systems, and dry electrode sheet technology precisely fills this gap. The wet process requires dissolving active materials, conductive agents, and binders in organic solvents such as NMP to form a slurry. After coating, high-temperature drying is needed to recover the solvent. However, residual solvents that cannot be completely removed during this process severely disrupt the ion conduction paths of solid electrolytes, leading to degraded battery performance. More critically, mainstream solid electrolytes like sulfide-based ones are highly sensitive to moisture and organic solvents, prone to hydrolysis reactions that generate harmful gases, directly compromising battery safety and cycle life.

The dry electrode sheet process, featuring "dry powder mixing - roll pressing for film formation - thermal lamination molding," fundamentally addresses the aforementioned issues. Its core workflow starts with the dry powder mixing stage, where high-speed shearing forces thoroughly blend active materials, conductive agents, and dry binders such as PTFE. This process enables the binder to form a three-dimensional fibrous network that tightly encapsulates various powder materials, laying the foundation for subsequent film formation. Next, in the roll pressing for film formation stage, the mixed powder composite is continuously pressed through temperature-controlled roll sets to form a self-supporting film with a certain degree of strength. This film can be stably formed without solvents, completely avoiding the interface contamination risks associated with the wet process.

For the thick electrode design required by solid-state batteries to achieve high energy density, the dry process demonstrates unique advantages. Guided by the "gradual thinning" process concept, a relatively thick initial film blank is first prepared, and then precisely thinned to the target thickness through multi-stage roll pressing. This enables the stable production of high-load electrodes without issues like cracking or uneven density commonly seen in thick coatings of the wet process. Finally, in the thermal lamination process, the electrode film and current collector are pressed and bonded under precise temperature control. The thermal adhesiveness of the binder ensures a strong interface bond, which not only guarantees ion conduction efficiency but also enhances the structural stability of the electrode.

Industrial Synergy: Cost Reduction and Efficiency Improvement Accelerating the Commercialization of Solid-State Batteries

The large-scale application of solid-state batteries has long been hindered by the bottleneck of high manufacturing costs, and dry electrode sheet technology is becoming a key driver to solve this cost challenge. In the wet process, solvent procurement, drying equipment investment, and solvent recovery account for over 30% of the energy consumption in battery production. Additionally, the wet process requires large equipment footprint and has a long production cycle. In contrast, the dry process eliminates these core links, achieving cost reduction and efficiency improvement throughout the entire chain: equipment investment is significantly reduced, production energy consumption is cut by more than 40%, and the overall manufacturing cost of battery cells can be lowered by 15% - 30%.

In terms of production efficiency, dry electrode sheets also hold distinct advantages. Since there is no need to wait for solvent drying and recovery, the production cycle of the dry process is shortened by more than 40% compared to the wet process. Moreover, integrated equipment can realize integrated operations of "film formation - thinning - lamination," greatly enhancing production continuity. This efficient production mode is well-suited to meet the future large-scale mass production needs of solid-state batteries, and a single production line can achieve higher film-forming speeds through parameter optimization, further expanding the capacity advantage.

More importantly, dry electrode sheets exhibit strong material compatibility. Whether it is sulfide, oxide, or polymer-based solid electrolytes, they can be adapted by adjusting dry mixing formulas and roll pressing parameters. Unlike the wet process, which requires repeated optimization of the slurry system for different electrolytes, the dry process significantly reduces the process adjustment costs during the technological iteration of solid-state batteries. This compatibility also extends to the adaptation of new electrode materials, such as the good combination with high-energy materials like silicon-based anodes, providing greater room for improving the energy density of solid-state batteries.

Technological Co-Evolution: A Positive Cycle of Demand-Driven and Technology-Supported Progress

The development of solid-state batteries and dry electrode sheets presents a positive cycle of "demand driving technology and technology supporting demand." On one hand, the pursuit of high conductivity and long cycle life in solid-state batteries is driving continuous breakthroughs in dry electrode sheet technology. To address the insufficient conductivity of early dry electrodes, the industry has optimized the dispersion process of conductive agents and developed "conductive - binding" integrated materials, bringing the electronic conductivity of dry electrode sheets close to or even reaching the level of wet electrode sheets. To solve the problem of easy breakage during the thinning of self-supporting films, technical measures such as introducing auxiliary binders to strengthen the fibrous network strength and using protective films for support have been adopted, significantly improving the mechanical properties and production yield of the films.

On the other hand, technological advancements in dry electrode sheets are also expanding the application boundaries of solid-state batteries. Thin electrodes prepared through precise control of roll pressing parameters can be adapted to scenarios such as flexible electronics and wearable devices, opening up a new consumer electronics track for solid-state batteries. The mature production of high-load thick electrodes is pushing the energy density of solid-state batteries toward higher theoretical limits, laying the foundation for extending the range of electric vehicles and reducing the full-life cycle costs of energy storage power stations.

This collaborative upgrading is also reflected in interface optimization. Through technologies like co-rolling, the dry process can realize the integrated formation of electrodes and solid electrolytes, establishing tight interface contact during the preparation process and reducing interface pores. This allows the battery to achieve excellent cycle performance even under low stacking pressure, with a capacity retention rate of over 80% after 500 cycles, clearing a key obstacle for the practical application of solid-state batteries.

From laboratory research to production line verification, the integration of dry electrode sheets and solid-state batteries has moved from a technological concept to industrial practice. As dry electrode sheet technology continues to make breakthroughs in areas such as binder fiberization control and equipment automation, and as solid electrolyte materials for solid-state batteries mature, the in-depth collaboration between the two will completely reshape the technological landscape of the lithium-ion battery industry. In the next 3 - 5 years, this "solvent-free + solid-state" technological revolution is expected to drive fields such as new energy vehicles and energy storage power stations into a new development stage characterized by higher safety, greater density, and lower costs.